Study on the property of boron carbide-modified phenol-formaldehyde resin for silicon carbide bonding

Study on the property of boron carbide-modified phenol-formaldehyde resin for silicon carbide...
Jiang, Haiyun; Wang, Jigang; Wu, Shenqing; Wu, Ruomei; Hu, Zhongliang; Zhang, Weili; Zhao, Xuehui
2014-10-16 00:00:00
Boron carbide powder (B4C) was added into phenol-formaldehyde (PF) resin to increase the high temperatural bond strength of PF resin. Using the modified PF resin silicon carbide block could be bonded satisfactorily even treated at 700–800°C, and its bond strength was higher than 20 MPa. The thermal modification mechanism was investigated by scanning electron microscopy, energy dispersive X-Ray, and pyrolysis gas chromatography spectrum coupled with a mass spectrum. The results indicate that B4C can increase the heat resistance of PF resin efficiently. B4C can not only seize some active groups of the resin matrix including phenolic hydroxyl and methylol, but also can hold the main components of some volatiles such as CO, H2O, phenol, and its derivations in the resin matrix by chemical reactions. At the same time, the reaction product boron oxide closes and mends the microcracks for its satisfactory wettability and adhesive capacity. In consequence, the efficient components escaping from the resin matrix can be sharply reduced. A relative intact skeleton of the resin is obtained, and its bond strength and thermal stability are remarkably elevated.
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Study on the property of boron carbide-modified phenol-formaldehyde resin for silicon carbide bonding

Abstract

Boron carbide powder (B4C) was added into phenol-formaldehyde (PF) resin to increase the high temperatural bond strength of PF resin. Using the modified PF resin silicon carbide block could be bonded satisfactorily even treated at 700–800°C, and its bond strength was higher than 20 MPa. The thermal modification mechanism was investigated by scanning electron microscopy, energy dispersive X-Ray, and pyrolysis gas chromatography spectrum coupled with a mass spectrum. The results indicate that B4C can increase the heat resistance of PF resin efficiently. B4C can not only seize some active groups of the resin matrix including phenolic hydroxyl and methylol, but also can hold the main components of some volatiles such as CO, H2O, phenol, and its derivations in the resin matrix by chemical reactions. At the same time, the reaction product boron oxide closes and mends the microcracks for its satisfactory wettability and adhesive capacity. In consequence, the efficient components escaping from the resin matrix can be sharply reduced. A relative intact skeleton of the resin is obtained, and its bond strength and thermal stability are remarkably elevated.